3 hours and 35 minutes + 2 hours and 45 minutes = 6 hours and 20 minutes.
3 hours + 2 hours = 5 hours
35 minutes + 45 minutes = 1 hour and 20 minutes.
60 minutes are in an hour. 45 minutes + 15 = 60
35 - 15 = 20
So 1 hour and 20 minutes.
Hope this is correct and helps you! (:
-Hamilton1757